The World
Record for the Heaviest Venomous Snake

The heaviest venomous
snake is probably the eastern diamondback rattlesnake (Crotalus adamanteus)
of sparse woodland and lowland coastal regions in the southeastern United
States. It averages 5.5-6.8Kg (12-15lb) and 1.52-1.83m (5-6ft) in length.
The heaviest on record weighed 15Kg (34lb) and was 2.36m (7ft 9in) long.

The gaboon viper (Bitis
gabonica) of tropical Africa is probably bulkier than the eastern
diamond, but its average length is only 1.22-1.52m (4-5ft). An exceptionally
long 1.83m (6ft) female weighed 11.34Kg (25lb) and another female measuring
1.74m (5ft 8.5in) weighed 8.2Kg (18lb) with an empty stomach.